Earlier exit signs used incandescent lamps. The earliest alternatives to incandescent lamps were radioactive tritium gas and compact fluorescent lamps. In 1985, light-emitting diodes (LEDs) were introduced for use in exit signs.
According to the National Fire Protection Association (NFPA), National Electrical Code (NEC), Underwriters Laboratories (UL), and local fire and building codes for each state, buildings that provide public access are required by law to have signs identifying the exits. These emergency signs are required to exhibit a specific amount of illumination and often times are required to have an emergency backup power source to provide illumination for a specified period of time when electrical power to the building is interrupted to allow sufficient time for persons in the building to vacate. LED exit signs are presently available with red or green color LEDs or other colors, as required by local ordinances or municipalities and depending on state and city codes.
The different red or green color output LED exit signs as required by local ordinances or municipalities, and adhering to state and city codes present a problem with the LED exit sign distributor. Often times, the wrong color LED exit sign is delivered and when this is the case, the original color LED exit sign is returned to the distributor and a replacement color LED exit sign is then shipped out again. With this frequent occurrence, the shipping costs can add up rather quickly. Having only one LED exit sign that can offer either red or green color is most desirable. The present invention will allow for this to occur without the use or additional cost for color selective switches. The final color output of the LED exit sign is determined by the color filter used with the integral color LEDs. Both red and green color filters will be supplied with each color LED exit sign using the color LED lamp of the present invention.
The LED lamp of the present invention turns on both the red and green color output LEDs simultaneously to produce a yellow color light. The combined yellow color light from the LEDs are then passed through either a red color filter to produce a red color exit sign indicia, or through a green color filter to produce a green color exit sign indicia.
The color LED exit sign works by filtering the LED light output from the color LED lamp to output the desired red or green indicia. Red and green are complementary colors that when additively mixed together, will produce the color yellow. Now when this color yellow is used with a red color filter, the red color filter absorbs the green LED colors and transmits the red LED colors, thereby producing only red color indicia for the exit sign. Likewise, when the same color yellow is used with a green color filter, the green color filter will absorb the red LED colors and will transmit only the green LED colors, thereby producing only green color indicia for the exit sign. It should be noted that the wavelengths of the red or green color filters should match closely with the wavelengths of the red or green color LEDs for the best and brightest color light absorption and transmission.
Exit signs usually include a stencil having perforations that define indicia through which the LED light passes and is readable by an observer. Existing stencil signs have solid colored green or red diffusion panels behind opaque sections with the letters EXIT cut out. Other exit signs can include a stencil manufactured out of a clear lens with the indicia or background masked with a red, green, or other color ink. The word EMT is usually white in this case against the color background. The indicia generally form the letters of the word EXIT and include removable or permanent chevron arrows located on opposite sides of the word EXIT. Other words, symbols, or ideogram indicia can indicate an exit. Among these are words or symbols in non-English speaking countries that have an analogous meaning to the word EXIT in English.
The present invention provides an LED lamp that enables a user to produce distinct color outputs. The color LED lamp is designed for use in illuminated signs generally including emergency exit signs, but also other types of illuminated signs that can be used in different locations. The use of the color LED lamp will allow the emergency signage to comply with all local fire and building code requirements. An LED exit sign manufacturer, wholesaler, and retailer can stock only one basic version of the color LED lamp exit sign thereby reducing manufacturing, inventory, and shipping costs. The color LED lamp is designed to replace existing incandescent and single color LED lamps. It can be used directly in sockets of existing emergency exit signs as retrofit LED lamps, or as the main light source in new emergency exit signs and other illuminated signs. Besides using the color LED lamp of the present invention in emergency exit signs, the color LED lamp can be used in illuminated advisory, directional, instructional, warning, and safety demarcation signs. Another area where the color LED lamp of the present invention can be used is in warning and instructional lighting markers used in many truck-loading docks around the country.
It is an object of the present invention to provide a color LED lamp, wherein one of the color red or the color green can be used for emergency lighting applications incorporating light emitting diodes as the main light source for use in existing and newly manufactured signage lighting fixtures.
Another object of the present invention is to provide a color LED lamp that can readily replace the incandescent and compact fluorescent lighting units offering energy efficiency, longer life with zero mercury, zero disposal costs, and zero hazardous waste. The present invention can be used in all types of emergency and illuminated signage.
Yet another object of the present invention is to provide a color LED lamp that will easily produce a mixed red and green color to produce the color yellow while using a relatively low number of colored LEDs, and wherein such use is in the field of emergency exit signs.
Yet another object of the present invention is to provide a color LED lamp that will easily produce monochrome yellow color light while using a relatively low number of colored LEDs, and wherein such use is in the field of emergency exit signs.
Yet another object of the present invention is to provide a color LED lamp that will easily produce white color light while using a relatively low number of white color output LEDs, and wherein such use is in the field of emergency exit signs.
A further object of the present invention is to provide a color LED retrofit lamp containing integral electronic circuitry that can be readily and economically fabricated from simple electronic components for easy adaptation for use with existing illuminated signage.
And yet a further object of the present invention is to provide a color LED lamp combined with surge suppression, uniform illumination, color filters, optical diffusers, battery backup, and low power consumption to be readily and economically fabricated from simple components, for use in newly manufactured and multipurpose illuminated emergency signage that is readily adaptable to comply with fire and building code.
A final object of the present invention is to provide a color LED lamp for use in newly manufactured illuminated signage with optional emergency lights integrally and operationally mounted with the main lamp unit.